how much do we really know?

How much do wereally know?

Sauropod Necks

Mike TaylorUniversity of Bristoldino@miketaylor.org.uk

Matt WedelWestern Universitymathew.wedel@gmail.com

Almost nothing, it turns out.

Why sauropod necks matter

Sander and Clauss 2008:fig. 1

The Berlin BrachiosaurThe Berlin Brachiosaur

The Carnegie The Carnegie DiplodocusDiplodocus

The Carnegie The Carnegie ApatosaurusApatosaurus

MamenchisaurusMamenchisaurus

Sauropod neck skeletons are misleading for three reasons.

1. Incompleteness

The Berlin Brachiosaur

Giraffatitan brancaiMB.R.2181

(HMN SII)

Janensch 1950bPlate VIII

The Berlin Brachiosaur

Giraffatitan brancaiMB.R.2181

(HMN SII)

Janensch 1950bPlate VIII

The Carnegie DiplodocusCM 84 & 82

Hatcher 1901Composite from

Plate III

The Carnegie DiplodocusCM 84 & 82

Hatcher 1901Composite from

Plate III

The Carnegie DiplodocusCM 84 & 82

Hatcher 1901Composite from

Plate III

Hatcher 1901Plate I

The Carnegie ApatosaurusCM 3018

Gilmore 1936Plate XXIV

The Carnegie ApatosaurusCM 3018

Gilmore 1936Plate XXIV

Why incompleteness?Why incompleteness?

Wedel et al. 2000

Taphonomy of Sauroposeidon

Gilmore 1925, plate XBaby Camarasaurus

Sauropod neck skeletons aremisleading for three reasons.

1. Incompleteness

2. Distortion

The Rutland Cetiosaurus

The Rutland Cetiosaurus

The Carnegie DiplodocusCM 84 & 82

Hatcher 1901Composite from

Plate III

Cervicals 2 and 3 of Cervicals 2 and 3 of GiraffatitanGiraffatitan HMN SI HMN SI

Wedel 2005

Why distortion?

Wedel 2005

Sauropod neck skeletons aremisleading for three reasons.

1. Incompleteness

2. Distortion

3. Absent cartilage

51cm41cm+25%

+25%

Not likely as much as 25% because a baby giraffe is:

A. a baby (though SII is also subadult)B. not a dinosaur

How much cartilage does a domestic turkey have in its neck?

255 mm turkey neckArticulated vertebrae are 226 mm long=> must add 12% to bone-only length

Domestic turkey

Domestic turkey

Anterior articulation

Domestic turkeyin ONP

16º

Domestic turkey

Synovial joint extendscentrum length by 12%

Domestic turkeyin true neutral pose

44º

Domestic turkeyneutral poses

28º difference

760 mm adult ostrich neckArticulated vertebrae are 701 mm long => must add 8% to bone-only length

(Matt Cobbley, pers. Comm.)

Were sauropod necks more likeThose of giraffes or birds?

Birds are more closely related.

BUT gross vertebral morphology ismore like that of giraffes, e.g.opisthocoelous articulations.

?

??

Domestic turkey, C8, posteroventral viewDomestic turkey, C8, posteroventral view

12 mm long12 mm longwhen freshwhen fresh

Domestic turkey, C8, posteroventral viewDomestic turkey, C8, posteroventral view

10 mm long10 mm longafter simmeringafter simmering

Domestic turkey, C8, posteroventral viewDomestic turkey, C8, posteroventral view

9.5 mm long9.5 mm longafter scrapingafter scrapingoff cartilageoff cartilage

Domestic turkey, C8, posteroventral viewDomestic turkey, C8, posteroventral view

A 9.5 mm zygapophysis gains 26%A 9.5 mm zygapophysis gains 26%in length with cartilagein length with cartilage

Domestic turkey, C8, posteroventral viewDomestic turkey, C8, posteroventral view

A 9.5 mm zygapophysis gains A 9.5 mm zygapophysis gains 26%26%in length with cartilagein length with cartilage

Dude, where's my cartilage?Dude, where's my cartilage?

* Complete, live neck* Complete, live neck* Lose soft tissue* Lose soft tissue* Lose intervertebral cartilage* Lose intervertebral cartilage* Lose zygapophyseal cartilage* Lose zygapophyseal cartilage* Lose some of the bones* Lose some of the bones* Crush the remaining bones* Crush the remaining bones

* Complete, live neck* Complete, live neck* Lose soft tissue* Lose soft tissue* Lose intervertebral cartilage* Lose intervertebral cartilage* Lose zygappophyseal cartilage* Lose zygappophyseal cartilage* Lose some of the bones* Lose some of the bones* Crush the remaining bones* Crush the remaining bones

Then try to digitally manipulate the results!Then try to digitally manipulate the results!

Bones do not tell us everything!

JOURNAL OF MORPHOLOGY 123:456-789 (2011)

Osteology of the trunk of the African Elephant (Loxodonta africana)

Simeon Halibutwrangler

Institut für Biologie, Universität Scheinken, Schinkenstraße, Schinkenschloss, Germany.

ABSTRACT Uh … Hey, wait! Look at that rabbit!

Sauropod neck skeletons aremisleading for three reasons.

1. Incompleteness

2. Distortion

3. Absent cartilage

Sauropod neck skeletons aremisleading for three reasons.

1. Incompleteness

2. Distortion

3. Absent cartilage

So what should we do?

Extant analogues? But what?Extant analogues? But what?

Extant analogues? But what?Extant analogues? But what?

In isolation, yields untestable orIn isolation, yields untestable ormisleading results.misleading results.

Phylogenetic bracketing

Phylogenetic bracketing

1. Bird and dinosaur pneumaticityO'Connor and Claessens 2005

2. Tetrapod neckpostureTaylor et al. 2009

3. More archosaur limb cartilageBonnan 2010

3. Archosaur limb cartilageHolliday et al. 2010

Alligator elbow

3. Yet more archosaur limb cartilageMallison 2010

3. Yet more archosaur limb cartilageMallison 2010

Extinct analogues?

Phylogenetic bracketing often gives answersthat are less precise but more accurate.

And so, the punchline:We must be prepared to accept rigidly

defined areas of doubt and uncertainty.

AcknowledgementAcknowledgement

Thanks to all the animalsThanks to all the animalsthat gave their lives forthat gave their lives fordissection.dissection.